I read a book years ago "How to talk so kids will listen, how to
  listen so kids will talk" in a child psych course. Great book -
  easy to read. I've applied a lot of those ideas in talking to
  adults and it works almost as well. I think the "don't" idea I
  first heard from an Tony Robbins cassette tape set back in '95.
  Part of NLP - neurolingustic programming which is interesting
  stuff. "